Method and device for the objective determination of capillary refill behavior on a human body surface

Patent metadata

Field	Value
Publication number	US-11839484-B2
Application number	US-202117333069-A
Country	US
Kind code	B2
Filing date	May 28, 2021
Priority date	May 29, 2020
Publication date	Dec 12, 2023
Grant date	Dec 12, 2023

Abstract

A method for the objective determination of capillary refill behavior on a human body surface in which a spatially and spectrally resolved optical detection is carried out by at least one detector device (1) at a skin surface area (2) having a predefined areal size and outer contour. Subsequently a predefined pressure p constant over the skin surface area (2) is exerted over a predefined time t1; and the pressure effect is ended after expiry of this time t1. The spatially and spectrally resolved optical detection is carried out by the detector device (1) and the respective capillary refill behavior is spatially and temporally determined at a time t2 up to which at least one first threshold value of the measurement values detected simultaneously with spatial resolution has reached the measurement value that had been optically detected before the start of the pressure effect.

First claim

The invention claimed is:

1. A method for the objective determination of capillary refill behavior on a human body surface consisting of
carrying out a spatially and spectrally resolved optical detection by at least one detector device with an optical detector device at a skin surface area having a predefined areal size and outer contour, and subsequently
exerting a predefined pressure p constantly over the skin surface area over a predefined time t 1 ; and
ending the pressure after expiry of this time t 1 ; and carrying out
the spatially and spectrally resolved optical detection by the at least one detector device and the respective capillary refill behavior is spatially and temporally determined at a time t 2 up to which at least one first threshold value of the measurement values detected simultaneously with spatial resolution has reached a measurement value that had been optically detected before a start of a pressure effect.

2. The method in accordance with claim 1 , wherein the pressure p is exerted on the skin surface area mechanically or pneumatically or hydraulically.

3. The method in accordance with claim 1 , wherein a combined device that is configured for detection and illumination is used as the at least one detector device.

4. The method in accordance with claim 1 , including placing an internally hollow pressing element completely surrounding an outer margin of the skin surface area in a region of the skin surface area and having a predefined dimensioning and geometrical design of a surface coming into direct contact with the skin surface area pressed with a predefinable pressure force F 2 onto the skin surface area during the time t 1 and a spatially and spectrally resolved optical detection of an image is also carried out in this skin surface area by the at least one detector device or by a further detector device before a start of the pressure effect in the skin surface area in which a hollow pressing element is brought into contact with the skin surface area, and on ending of the pressure effect on the skin surface area, the hollow pressing element is removed and a repeat spatially and spectrally resolved optical detection of measurement values is also carried out in the skin surface area, and the measurement values detected before the start of the pressure effect are compared with the measurement values detected after removal of the hollow pressing element.

5. The method in accordance with claim 1 , including performing a two- or three-dimensional spatially resolved detection of topology of the skin surface area by the at least one detector device before the start of the pressure effect and up to after the end of the pressure effect; and
carrying out an evaluation of temporal restoring behavior by a comparison of the measurement values detected before and after the pressure effect.

6. The method in accordance with claim 1 , including carrying out a three-dimensional spatially resolved detection of topology of the skin surface area by the at least one detector device or by a further detector device before the start of the pressure effect exerted by a pressing element and up to after the end of the pressure effect; and
carrying out an evaluation of temporal restoring behavior by a comparison of the measurement values detected before and after the pressure effect in the skin surface area in which the pressing element was in contact with the skin surface area.

7. The method in accordance with claim 1 , wherein only wavelengths of colors of human skin surface occurring before, during, and after the pressure effect or a pressure force effect is considered in a spectrally resolved detection.

8. The method in accordance with claim 1 , including determining the changes of the spatially and spectrally resolved optical detection measurement values occurring after an end of the pressure effect from an outer margin of the skin surface area in direction of center of area or in opposite direction.

9. The method in accordance with claim 1 , with the start of the pressure effect on the skin surface area, detecting time up to which a minimum number of individual measurement values by the at least one detector device have a proportion in wavelength range between 570 nm and 650 nm below a second threshold value and thus blanching time is determined.

10. A device for carrying out the method in accordance with claim 1 , wherein a device is present by means of which the predefined pressure p is exerted on the skin surface area over the predefined time t 1 and the skin surface area by means of which the at least one detector device configured for the spatially and spectrally resolved optical detection can be monitored is arranged such that a spatially and spectrally resolved optical detection of measurement values can be achieved in the skin surface area before, during, and after the predefined pressure exertion, and the at least one detector device is connected to an electronic evaluation unit or the electronic evaluation unit is integrated in the at least one detector device that is configured to carry out a comparison of the measurement values detected before, during, and after the pressure effect and to determine the time up to which a settable minimum amount of the measurement values detected with spatial resolution have reached a measurement value that had been optically detected before start of the pressure effect.

11. The device in accordance with claim 10 , wherein the predefined pressure p can be applied to the skin surface area by means of a mechanical device by which a stamp is present that temporarily acts on the skin surface area or hydraulically or pneumatically, in which a gas or a liquid acts in a correspondingly compressed manner directly via an internally hollow pressing element or via the at least one detector device on the skin surface area.

12. The device in accordance with claim 10 , wherein a stamp or the at least one detector device is/are arranged in an interior of an internally hollow pressing element that can be temporarily brought into contact with the skin surface area while surrounding the skin surface area from the outside or
a gas or liquid temporarily compressed to the predefined pressure p in the interior of a hollow pressing element is introducible for the pressure effect on the skin surface area.

13. The device in accordance with claim 1 , wherein a pressure or force sensor configured for the continual determination of pressure acting on the skin surface area or of the force acting on the skin surface area is present.

Assignees

• Fraunhofer Ges Forschung

Inventors

• Vogel Uwe
• Richter Bernd
• Richter Torsten

Classifications

• A61B5/442 Primary

  Evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment · CPC title

• A61B5/0053

  by applying pressure, e.g. compression, indentation, palpation, grasping, gauging · CPC title

• A61B5/0059

  using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455) · CPC title

• A61B5/449

  Nail evaluation, e.g. for nail disorder diagnosis · CPC title

• A61B2560/04

  Constructional details of apparatus · CPC title